Film advancing mechanism for motion picture apparatus



March 20, 1934. R; c. MccLAY FILM ADVANCING MECHANISM FOR MOTION PICTURE APPARATUS Filed July 27, 1932 INVENTOR- Ru Y E. MCELH Y.

% ATTORNEY.

Patented Mar. 20, 1934 UNITED STATES PATENT FFlCE FILM ADVANCIN G MECHANISM FOR MOTION PICTURE APPARATUS Roy C. McGlay, Hollywood, Calif. Application July 27, 1932, Serial No. 624,918 4 Claims. (01. 88--13.4)

The invention relates to film advancing mechperfectly projected when the device is used in a anism for imparting a step-by-step movement motion picture projector. to a motion picture film. Also, it is eminently desirable that the register An object of the invention is to provide a simpins 2 should enter and leave a perforation in pie mechanical movement, avoiding the use of the him in a perfectly straight line therewith at cams which wear out and are expensive to reright angles to the film, whereby any sawing moplace, and also to substantially avoid a sawing tlOll, which destroys the edges of a perforation movement of the shuttle fork at the limits of its and eventually breaks through the edge of the movement as this would puncture the film ad- 111m, may be eliminated. 10 jacent the apertures therein. In avoiding the use In order to effect such a movement, housing 3 of cams, applicant employs operating members is mounted upon a film guide plate 4 to receive having cylindrical bearing surfaces whereby a the register pins 1 and to allow them to move very quiet operation of the film advancing mechonly in a straight line, at right angles to the line anism is obtained. of movement of the film. l5 These objects are further accomplished by op- The plate 4 is held in place by means of the crating the shuttle fork, and the register pin also, two outwardly extending arms 5 and 6 which are if desired, by means of a plurality of link memfastened at one end to the plate 4 by means of bers, one of which serves to move the shuttle the screws 7 and 8 and to the supporting base fork along the film gate and the other of which 9 by the screws 10 and 11. The register pins 1 20 serves to insert the shuttle fork into and retract are suitably fastened to a depending bracket 12, it from the film apertures, these link members which forms the inner edge of a fork (not shown). and the eccentrics which operate them being so Fastened to the center of the bracket 12 is a related that at the limit of movement of the shutrod or shaft 13, supported by a slide bearing 14 tle fork, it is inserted or retracted without being mounted on the plate 9. The register pins 1 v, 25 moved substantially along the film gate whereby are reciprocated by means of a link 15, slidably a sawing movement thereof is substantially premounted in a rocker bearing 16, fastened to the vented. rod 13 at a point between the slide bearing 14 For further details of the invention reference and the bracket 12. may be made to the drawing, wherein: Link 15 is supported by a rocker bearing 1'7 30 Fig. 1 is a side elevation of the intermittent mounted on the plate 9 and is pivotally connected film advancing mechanism and afilm guide plate at its lower extremity to a slide bearing 18 therefor. fastened to a shuttle fork or yoke 19. The link Fig. 2 is a front elevation of the mechanism member 15 rocks about the bearing 17 as a showing the film gate. pivot point, the sliding connection 16 being above 35 Fig. 3 is a side elevation of the shuttle fork the pivot point 17 and the sliding connection 18 or yoke, embodying the pull-down pins of the being below the pivot point 17. Thus, it will invention. be seen that the link member 15 above the pivot Fig. 4 i a, plan vi of th h ttl fork of point 17 follows the motion imparted to the shut- Fjg. tie fork 19 and imparts this motion to the reg- 40 Referring more particularly to the drawing, ister pins through the rocker bearing 16 and 951 the rod 13. in the operation of a motion picture camera it is essential that the register pins 1 (Fig. 1) enter The Shuttle fork 19 E 1 and 3) m the form of a yoke. Extending irom one slde of the a perforation 1n the film (not shown) consecuf k 1 h it 20 t 11 t d tive1y with the withdrawal from the film of the or 9 IS s a W m is plvo y suppor e 5 p pins 2 so that the film will be held by a rocker bearing 21, about which point the shuttle fork 19 pivots. The bearing 21 is mount- Sta'tmna'ry while the pun'down pms 2 are ed on the supporting base 9 away from the beartumed to Position Where they once again ing 18 and the pull-down pins 2. In front of the 'gage the bearing 18, the fork 19 extends in substantially i 50'" It is desirable that this interval of time duran elgngated 0 Shape, ing which the film iS d S at o a y, should At one endof the O in fork 19 is an inwardly be as long as conveniently possible so that the extending boss 22, adjacent the bearing 18 to negative film in a camera may be properly exwhich is pivotally fastened a link member 23. posed by allowing a wide-angle shutter open-- The opposite end of the link member 23 is pivotal- 1; 55 ing, and so that a picture may be completely and 1y journalled to a pin member 24, eccentrically mounted on a gear 25. Gear 25 meshes with a second gear 26 mounted above gear 25. These gears may be of fabric or suitable helical gears in order to eliminate the possibility of noise or they may be entirely dispensed with as will be easily understood by those skilled in the art.

A link member 27 is pivotally fastened at one end to a boss extension 28 on the fork 19 and at its other end is journalled to a pin member 29, eccentrically mounted on the gear 26. The link members 23 and 27 and their respective eccentrics 25 and 26 are so related, that each link member imparts minimum movement to the shuttle fork 19, when the other link member imparts maximum movement to fork 19. In other words, the pins 2 will enter and be drawn out of the film sprocket holes when the points 28, 27 and the center of the gear 26 form substantially a straight line, and so that a line between the axis of rotation of the eccentrics 25 and 26 is substantially at right angles to a line joining the axis of rotation of eccentric 25 and the center of rotation of bearing 21.

Thus, it will be seen that the pins 2 will enter and be withdrawn from the film practically at right angles thereto, so that a sawing motion may be substantially eliminated.

Similarly, when the link member 27 is imparting its maximum movement, either up or down, to the shuttle fork 19, the points 22, 24 and the center of the gear 25 are substantially in a straight line, whereby a minimum amount of movement is imparted to the pins 2 by means of the link 23.

By locating the center of rotation of the link 1 member 23 at a distance from the pins 2, a long,

narrow arc of travel is imparted to the pins 2, which means that they move substantially in a straight line, parallel to the film plate l.

The gear 26 is positively driven by means of a l shaft 30 fastened thereto (Fig. 2) which in turn drives the rest of the mechanism. The plate 4 has a film gate aperture 31, apertures 32 and 33 for the register pins 1 and apertures 34 and 35 for the pull-down pins 2, as is well understood.

It will be obvious that various modifications, such as a different film gate or a mutilated yoke member, may be introduced without departing from the inventive spirit herein conceived.

Having thus described the invention, what is claimed as new and desired to secure by Letters Patent is:

1. Film advancing mechanism comprising a shuttle fork, an operating member therefor, a plurality of eccentrics, a link member connected at one end to said operating member and at the other end to one of said eccentrics, another link member connected at another point to said operating member and to another of said eccentrics, said link members and eccentrics being so related that one of said eccentrics and its associated link member imparts minimum movement to said shuttle fork when another eccentric and its associated link member imparts maximum movement to said shuttle fork, whereby a sawing movement of said shuttle fork at the limits of its movement is substantially prevented.

2. Film advancing mechanism comprising a shuttle fork, an operating member therefor, a fixed slide bearing for said member, a plurality of eccentrics, a link member connected at one end to said operating member and at the other end to one of said eccentrics, another link member connected at another point to said operating member and to another of said eccentrics, said link members and eccentrics being so related that each of said eccentrics and its associated link member imparts minimum movement to said shuttle fork when the other eccentric and its associated link member imparts maximum movement to said shuttle fork, whereby a sawing movement of said shuttle fork is substantially prevented.

3. Film advancing mechanism comprising a shuttle fork, an operating member therefor, a fixed slide bearing for pivotally supporting said member, a plurality of inter-meshing gears, a link member connected at one end to said operating member and at the other end eccentrically to one of said gears, a second link member connected at another point to said operating member and eccentrically to a second of said gears, said link members being so related that each link member imparts minimum movement to said shuttle fork when the other link member imparts maximum movement to said shuttle fork and vice versa, whereby a sawing movement of said shuttle fork, at the limits of its movement, is substantially prevented.

4. Film advancing mechanism comprising a shuttle fork, an operating member therefor, a stationary slide bearing for said operating member, an eccentric for reciprocating said shuttle fork substantially horizontally, a link connected at one end to said eccentric and at the other end to said operating member, another eccentric for reciprocating said shuttle fork substantially vertically, a link member connected at one end to said second-mentioned eccentric and at the other end 

